Ground-Piercing Radar on NASA Mars Orbiter Ready for Work

NASA's Mars Reconnaissance Orbiter has extended the long-armed antenna of
its radar, preparing the instrument to begin probing for underground layers
of Mars.

The orbiter's Shallow Subsurface Radar, provided by the Italian Space Agency,
will search to depths of about one kilometer (six-tenths of a mile) to find and
map layers of ice, rock and, if present, liquid water.

The radar's antenna had remained safely folded and tucked away throughout the
flight to Mars from Aug. 12, 2005, to March 10, 2006, and while the orbiter used
the friction of dipping into the top of Mars' atmosphere 426 times in the past
six months to shrink the size of its orbit. Latches on the restraints were popped
open on Sept. 16, and the spring-loaded twin arms of the antenna unfolded themselves.
Subsequent information from the spacecraft indicates that each arm properly extended
to its 5 meter (16.4 feet) length.

"The deployment of the antenna has succeeded. It went exactly as planned," said Dr.
Enrico Flamini, the Italian Space Agency's program manager for the Shallow Subsurface
Radar. "Now the excitement builds about what the radar will find hiding beneath the
surface of Mars."

A radar-team engineer at NASA's Jet Propulsion Laboratory, Pasadena, Calif., Ali Safaeinili,
said, "Motion sensors on Mars Reconnaisance Orbiter gave us good evidence that the antenna
had deployed successfully. The amount of antenna vibrations as the arms unfolded was
within the range anticipated."

The radar received its first radio echo from the Martian surface during a test on Sept.18,
providing a preliminary indication that the entire instrument is working properly. Researchers
will use the instrument for more test observations at the end of this month. Communication with
all spacecraft at Mars will be intermittent during most of October while that planet is behind
the sun from Earth's perspective. The two-year-long main science phase of the Mars Reconnaissance
Orbiter mission will begin in November.

"We will use the Shallow Radar to map buried channels, to study the internal structure of ice
caps and to see boundaries between layers of different materials," said Dr. Roberto Seu of the
University of Rome La Sapienza, leader of the instrument's science team. "The data will provide
our first detailed look just under the Martian surface, where ices might reside that would be
accessible for future explorers."

The radar instrument on the Mars Reconnaissance Orbiter will complement a similar instrument
that went into use last year on the European Space Agency's Mars Express orbiter, the Mars Advanced
Radar for Subsurface and Ionospheric Sounding. The two instruments use different radar frequencies.
The one on Mars Reconnaissance Orbiter can discriminate between thinner layers, but cannot penetrate
as deep underground, compared with the one on Mars Express. Both result from Italian and American
partnership in using radar for planetary probes.

Alcatel Alenia Spazio-Italia, in Rome, is the Italian Space Agency's prime contractor for the
instrument. Astro Aerospace, of Carpineria, Calif., a business unit of Los Angeles-based Northrop
Grumman Corp., developed the antenna as a subcontractor to Alcatel Alenia.

Further information about the Shallow Subsurface Radar is online at www.sharad.org . For more
detailed information about the Mars Reconnaissance Orbiter, see www.nasa.gov/mission_pages/MRO/main .
The mission is managed by JPL, a division of the California Institute of Technology, Pasadena, for
the NASA Science Mission Directorate, Washington. Lockheed Martin Space Systems, Denver, is the
prime contractor and built the orbiter.